Students are also introduced to the geometric terms circle and triangle. Students develop their intuitive understanding of circles and triangles. They may incorrectly identify shapes in this activity, such as identifying an oval as a circle. If this happens, acknowledge the similarities between the shapes (“Esta figura es curva como un círculo, pero no es un círculo” // “This shape is curved like a circle, but it is not a circle.”) As students sort examples and nonexamples of triangles in the second activity, they continue to build their informal understanding of what is a triangle.

How did students think of triangles as they came into the lesson? In what ways did their understanding of triangles change upon completing the lesson?